1. Field of the Invention
The present invention is broadly concerned with an apparatus for deep fat frying which includes a cooking vessel having a bottom wall with a central elevated portion and a support assembly complementally configured to the cooking vessel to hold the cooking vessel in a desired orientation and position a heating source so as to promote convection of the liquid cooking medium in the cooking vessel. When the heat source is activated, and more particularly below the central elevated portion, the heat source directs the heat generated thereby toward the bottom of the cooking vessel, convection currents are produced which result in more uniform heating of the liquid cooking medium and further aid in depositing loose food particles in troughs in the cooking vessel positioned laterally of the central elevated portion.
2. Description of the Prior Art
Deep fat fryers are generally known and used for frying many kinds of food in oil or fat. Typically, such devices consist of a cooking vessel (e.g., a pan, kettle, skillet or the like) which is filled with a cooking medium, such as oil, fat or shortening. The cooking vessel is placed over a heating element of an electric range or burner whereby, when the heating element is activated to heat the oil therein, food is deposited into the heated cooking medium for a desired period of time until the cooking process is completed and the food items are removed. Many types of food items such as poultry, fish, potatoes and the like may have various coatings, such as a flavored coating, breading or batter on the outside of the food item. Some portion of the coatings are inevitably separated from the food item during the cooking process and are either suspended in the heated cooking medium or drop to the bottom of the vessel. One type of deep fat frying apparatus which has enjoyed recent popularity for outdoor usage employs a large cylindrically shaped pan of a size sufficient to receive a turkey therein, the pan being positioned over a gas burner of a tripod pan support. The burner is positioned such that it is directly below the flat bottom of the cylindrically shaped pan, and thus the flames of the burner provide direct heating such that the bottom surface of the pan is the hottest region.
While such cooking devices provide for a relatively effective frying of the food, several problems exist with these conventional devices. First, the traditional positioning of the heating elements used to heat the cooking vessel do not provide an even temperature throughout the cooking medium. The temperature differential within the cooking medium attributable to direct heating of the bottom surface of the vessel is exacerbated when the cooking takes place in an outdoor environment, with cooler air surrounding the vessel sidewall. Specifically, a traditional flame burner or electric range heating element will provide most of the heat directly to the bottom wall of the cooking vessel and thus the highest temperature is found on the bottom wall and in the cooking medium immediately adjacent thereto. This concentration of heat at the flat bottom portion of the cooking vessel results in an uneven cooking temperature in that the cooking medium directly above and across the bottom portion of the cooking vessel heats to a higher temperature than the cooking medium in the upper depths of the vessel or along the sidewall(s). thus, food products placed in the cooking vessel may not cook evenly due to their position within the fryer. In the case of some items where the extent of cooking may not be readily detected, this may represent a danger to the user in that bacteria may not be completely eliminated within the food item.
Another problem associated with conventional frying apparatus is that elevated temperature at the bottom of the cooking vessel may result in fat breakdown with associated deterioration in flavor. This may also result in the inability to reuse the fat or oil for cooking subsequent batches of food items. A further disadvantage commonly associated with conventional deep fat frying apparatus is that when the cooking medium reaches an inappropriately high temperature, the cooking medium may catch on fire and cause a danger to the surroundings as well as the user. When the cooking medium is too hot and moisture is present, the moisture may flash and burn the user.
The separated coating particles on some food items will often drop onto the bottom surface of the cooking vessel which is often immediately above the heating element. As a result, these pieces of coating, skin, or other particles, referred to by those in the art as xe2x80x9ccracklings,xe2x80x9d will burn or blacken and then may attach to the food items in the medium. This detracts from the taste and appearance of the food items. Further, if the temperature at the bottom of the vessel is too high, the cracklings may burn causing oxidation of the cooking medium, thereby reducing its useful life.
There has thus developed a need for an improved deep fat frying apparatus which maintains a more even heating of the cooking medium within the cooking vessel.
There is also a need for a deep fat frying apparatus which helps to prevent the deposit of cracklings over the hottest area of the pan.
There is a further need for a deep fat frying apparatus where the heat source is positioned relative to the cooking vessel to promote improved cooking without burning the food items or cracklings within the vessel.
These and other needs have largely been met by the deep fat frying apparatus of the present invention. That is to say, the deep fat frying apparatus hereof includes a uniquely configured cooking vessel in combination with a complementally configured heater support assembly which provides improved circulation of the cooking medium, provides a more efficient use of the heat source, provides for depositing cracklings in an area of the vessel remote from the heat source, and maintains a more even temperature of the cooking medium throughout the cooking region of the vessel. The deep fat frying apparatus hereof is configured to provide a pattern of convection currents which both avoids overheating of the cooking medium, provides more consistent temperatures, and separation and removal of cracklings from the cooking area.
Broadly speaking, the present invention includes a cooking vessel with a bottom wall having a longitudinally extending elevated central portion, sloping wall surfaces, and preferably at least one trough which is positioned along an upright sidewall, and a support assembly which includes a heating element and a frame support. The frame support is configured to hold the cooking vessel in a desired orientation whereby the heating element is aligned in registry with and positioned below the elevated central portion.
In preferred embodiments, the cooking vessel is provided with sidewalls and end walls which are of different lengths to facilitate orientation of the cooking vessel within the frame. Handles are coupled to the sidewalls or end walls to facilitate lifting of the cooking vessel. The sloping wall surfaces each have an outboard margin and an inboard margin which cooperatively define a ridge along the elevated central portion. The maximum horizontal width of each of the sloping wall surfaces being at least one fourth of the width of the endwalls. The downward sloping wall surfaces preferably have a slope relative to the horizontal between 4xc2x0 and 30xc2x0 and more preferably between about 10xc2x0 and 20xc2x0. Preferably, a trough is provided adjacent each sidewall and have an upright, preferably vertical barrier wall which help to collect and hold the cracklings received therein. The central elevated region and sloped surfaces help to prevent burning and overheating of the cooking medium as well as more evenly receiving heat from the heating source by increasing the distance between the central elevated region directly above the heat source, providing surfaces which are oriented in facing relationship to the heat source, and by the end walls and barrier walls which help to hold the greatest concentration of heat generated by the heat source inboard of the troughs.
The sidewalls or endwalls preferably include a plurality of inwardly facing retaining ledges which are positioned to receive and hold a perforate grate onto which food to be cooked may initially descend and held at a desired depth within the cooking medium. The ledges are preferably positioned so that the grate is maintained substantially horizontal during cooking, and most preferably positioned so that the grate is also supported by the ridge of the elevated central portion. The sidewalls, end walls and bottom wall together form a housing, and may be constructed of any metal which provides good heat conductivity such as aluminum, copper, brass or stainless steel. Stainless steel, because of its resistance to corrosion and its cleaning properties, is the preferred material for the grate and the housing.
The support assembly has a frame which is sized and shaped to receive the cooking vessel in a desired orientation whereby the cooking vessel is held within the frame and supported thereon with its central elevated portion positioned directly above and aligned in registry with the heat source. Particularly preferred results are achieved when the heat source is provided as an elongated gas burner with a plurality of openings to direct flames upwardly. The heat source may be vertically adjustably carried by the frame to vary the distance between the heat source and the elevated central portion while maintaining alignment of the heat source beneath the elevated central portion, or the heat source may be fixedly mounted to the frame. It is generally desirable that the cooking medium within the vessel be heated to a temperature above 300xc2x0 F. in order to provide satisfactory cooking to brown the food items without undue delay. The amount or intensity of heat supplied by the heat source may be varied by either adjustment of its position, as noted above, or by increasing the energy supplied to the heat source by a gas valve or rheostat in the case of an electric heating element.
The frame of the heater support assembly is constructed of iron or steel to be sufficiently rigid to provide a stable support for the cooking vessel when filled to a desired depth with the cooking medium. Preferably, the frame substantially surrounds the heat source and provides a central open area for the admission of air therein. A ledge is provided in the frame around the central open area for supporting the cooking vessel thereon. A plurality of legs elevate the frame above a supporting surface to position the frame and thus the cooking vessel at a convenient height while in use.
The deep fat fryer apparatus is used by filling the cooking vessel with a cooking fat such as lard or shortening or a cooking oil and then placing the vessel on the frame so that the elevated central portion is positioned in registry over the heat source. The heat source is activated, such as by opening a valve to admit gas and igniting the burner. The positioning of the heat source beneath the central elevated portion, the perforate grate, and the sloping wall surfaces allows the heated cooking medium to circulate by convection with the hottest part of the medium circulating upwardly from the elevated central portion. The convection currents then move outwardly toward the sidewalls, where they are cooled and move downwardly toward the troughs, then inwardly toward the elevated central portion, moving through the perforate grate. When a satisfactory cooking temperature for the cooking medium above the grate has been reached, preferably between about 300xc2x0 F. and 400xc2x0 F. and most preferably between about 345xc2x0 F. to 350xc2x0 F., a food item is deposited into the vessel and falls to the grate. The length of time the food item remains in the cooking vessel depends on the type of food item, the quantity, the depth of the medium, and its temperature. However, the convection currents continue during cooking, which have the effect of carrying the cracklings outwardly and depositing them in the troughs, where they are retained. The sloping wall surfaces also help to direct more dense cracklings to the troughs by gravity. Additionally and most beneficially, the temperature of the cooking medium in the troughs will be about 30xc2x0 F. cooler than the temperature of the cooking medium in the cooking zone, i.e. above the grate. This not only promotes even cooking of the food items, but beneficially avoids overheating of the cooking medium in any one region and blackening or burning of the cracklings.
These and other advantages will be readily apparent to those skilled in the art with reference to the drawings and detailed description which follows.